One of these 50 things is the humble tally stick – a little-known curiosity of medieval monetary history which turns out to have much to teach us about both the nature of modern finance and how we think of it.

The episode – which like all of Tim Harford’s writings and broadcasts is concise, witty, and comes strongly recommended by me – is available online here.

My own book Money: The Unauthorised Biography is kindly mentioned as a source – and you can watch me giving a talk about the topic here if you are interested in following the story a little further.